Sodium hypochlorite solutions are commonly used and highly effective as bleaches and sanitizers for cleaning a variety of surfaces. However, sodium hypochlorite solutions are extremely corrosive to many treated surfaces, in particular, metal surfaces become highly corroded and discolored. Hypochlorite solutions corrode surfaces as a result of its composition of sodium hypochlorite, sodium chloride and often sodium hydroxide, each having distinct mechanisms of corrosion. Sodium hypochlorite is a strong oxidant causing metal corrosion through a redox attack. Sodium chloride attacks and penetrates the passivation layer of metals, resulting in pitting of the surface. In addition, sodium hydroxide is corrosive to metals as a result of formation of metal hydroxide. Additional descriptions of the mechanisms of corrosion are disclosed in Corrosion Basics, National Association of Corrosion Engineers, 1984.
Despite the corrosion caused by hypochlorite solutions on various surfaces, there remains a need for effective cleaning, disinfecting and/or sanitizing using hypochlorite solutions. In particular, industrial settings often rely upon the cleaning, disinfecting and/or sanitizing efficacy of oxidizing compositions employing hypochlorite. The healthcare market, namely hospitals, use hypochlorite compositions for its efficacy in killing bacterial spores, such as C. difficile. Therefore, it is an objective of the claimed invention to develop corrosion inhibitor compositions suitable for use with hypochlorite solutions on a variety of surfaces.
Various cleaning wipes have long been used for a variety of purposes. Cleaning wipes have contained various compounds to accomplish their intended purpose. For example, commercially-available cleaning wipes have included hypochlorite solutions, which are particularly well suited for use in cleaning, disinfecting and/or sanitizing. However, as is well recognized, the various commercial formulations including hypochlorite in saturated wipes result in significant discoloration and corrosion on the treated surfaces. Therefore it is a further objective of the invention to provide methods for hypochlorite corrosion inhibition, including the use of saturated wipes comprising the hypochlorite solution and the corrosion inhibitors according to the invention.
It is a further objective of the claimed invention to develop corrosion inhibitor compositions to simultaneously prevent all corrosive mechanisms of sodium hypochlorite solution on metal surfaces, including both corrosion and discoloration.
A still further object of the claimed invention is a corrosion inhibitor composition capable of preventing metal corrosion caused by sodium hypochlorite solutions without adversely impacting the stability of the hypochlorite solution.